Like Shakespeare’s Macbeth, Boris Godunov is capable of murder in pursuit of power. When Boris’s political opponents substitute a pretend descendant of the previous tsar, the so-called Pretender, to stage a coup d’état, Godunov, tormented by remorse, is certain that it is the reincarnation of his victim who, like an angel of vengeance, has come to take his life. Based on a play by Aleksandr Pushk...